Geothermal Cooling System for an Energy-Producing Plant

ABSTRACT

An improved electrical-utility steam-turbine power-plant cooling system including a condenser with heat-exchange surfaces and cooling means. The cooling means has a closed-loop system with an intake, a discharge and a cooling portion. Substantially all of the cooling portion is tunneling beneath the surface of the Earth. Water substantially fills the closed-loop system and a pump facilitates flow through the closed-loop system whereby water flows through the tunneling and is geothermally cooled.

FIELD OF THE INVENTION

This invention is related generally to a closed-loop condensate cooling system for steam-turbine power-plants and more particularly to a closed-loop cooling system which utilizes geothermal temperature differential to cool water contained within the closed-circuit cooling system.

BACKGROUND OF THE INVENTION

The current method in cooling condensate of a steam-driven turbine is by use of a water cooling tower. Cooling towers are large towers over which hot condensate cooling water is pumped to the roof of the tower and cascades down the outer portion of the tower over a diffusing structure, such as fins or a mesh. Traditionally, cooling towers have a plurality of large fans located on the roof of the tower which pull air through the outer skin of the cooling tower causing evaporative cooling of the hot water. The relatively cool water collects in a basin at the bottom of the cooling tower and is recirculated through the condensate cooling system.

The amount of water which evaporates is substantial and water is continually added to compensate for water loss. A water source, such as a lake or municipal supply, must be readily available to provide the necessary water, and consequently, locations of power plants are limited. In addition, the cooling water must be treated for contaminants to avoid damage to pumps, valves, and auxiliary equipment and to minimize pipe corrosion and because the make-up water is substantially untreated, water treatment costs are considerably high.

Cooling towers of the prior art have a number of problems and shortcomings. One shortcoming is the need for a large constant water source. Some cooling towers of the prior art use cooling water directly from lakes or streams. Oftentimes, such a system discharges pollutants along with the used water into the lakes and streams. This can have a harmful effect, including that pollutants are discharged into the body of water, but also because when the used water is discharged into a lake or stream it raises the temperature of that body of water. It would be desirable to have a closed-loop condensate cooling system for steam-turbine power-plants which minimizes system water loss and would not require a large reliable water source for condensate cooling purposes. Having a system such as this would allow power plants to be located in areas which are not in close proximity to a large and reliable body of water necessary to satisfy continual make-up water needs.

Another shortcoming of cooling towers in the prior art is the maintenance of the cooling tower fans and cooling tower diff-users. It would be desirable to have a closed-loop condensate cooling system for steam-turbine power-plants which does not require a cooling tower and consequently a cooling tower fan.

Yet another shortcoming of cooling towers in the prior art is the time and expense involved in treating the water for contaminants. It would be desirable to have a closed-loop condensate cooling system for steam-turbine power-plants which reduces the time and costs involved in continuous large scale water treatment.

Another problem in the cooling tower prior art is the ability to procure the necessary licensing/permits from local governments with respect to the installation and use of cooling towers. It would be desirable to have a closed-loop condensate cooling system for steam-turbine power-plants which does not require a cooling tower, and therefore, would not require the licenses and/or permits necessary for such cooling tower.

This invention meets these needs and overcomes other problems and shortcomings in the prior art with a closed-loop condensate cooling water system for use in electrical-utility steam-turbine power-plants that is not wholly reliant on a large nearby water source. This invention also eliminates the costs and maintenance of cooling towers and related equipment, decreases the expense and time involved in water treatment and in obtaining municipal permits/licenses.

OBJECTS OF THE INVENTION

It is an object of this invention to provide a condensate cooling system that is not reliant on a large nearby water source.

Another object is to eliminate cooling tower costs and maintenance and related equipment.

Yet another object is to provide a condensate cooling system which decreases the expense of water treatment.

A further object of this invention is to decrease or eliminate the time and expense of obtaining local authorization in the construction and use of cooling towers.

These and other objects of the invention will be apparent from the following descriptions and from the drawings.

SUMMARY OF THE INVENTION

This invention is a closed-loop condensate cooling water system for use in electrical-utility steam-turbine power-plants which utilizes the geothermic temperature differential of the Earth to cool the condensate cooling water. The cooling means comprises a closed-loop system having an inlet, a discharge and a cooling portion, substantially all of the cooling portion is tunneling beneath the surface of the Earth. The cooling means also includes water which substantially fills the closed-loop system and a pump which facilitates flow through the closed-loop system. The water flowing through the tunneling is geothermally cooled.

In a preferred embodiment, the cooling system includes more than one pump and the at least one pump maintains adequate water flow through the closed-loop system. In a highly preferred embodiment the tunneling is in a generally horizontal configuration. It is most preferred that the tunneling has multiple connecting portions and that water flows between the tunneling in substantially one direction. In an alternate embodiment, the tunneling includes a connecting portion located within the Earth and the tunneling is in a generally vertical configuration.

It is highly preferred that the tunneling is comprised of piping and includes a lining material. Preferably the cooling system is a replacement for an industrial cooling-tower cooling system.

In a method of cooling condensate water in an electrical-utility steam-turbine power-plant cooling system the following steps are highly preferred. Water is pumped through subterranean tunneling having a connecting portion at the distal ends thereof whereby the water flowing through the tunneling is geothermally cooled.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate a preferred embodiment including the above-noted characteristics and features of the invention. The invention will be readily understood from the descriptions and drawings. In the drawings:

FIG. 1 is a schematic drawing showing a preferred embodiment of the invention having a horizontal subterranean bed and multiple pumps.

FIG. 2 is a schematic drawing showing another embodiment of the invention having a vertical subterranean bed.

FIG. 3 is a schematic drawing showing a highly preferred embodiment of the invention having a horizontal subterranean bed with multiple connecting portions.

FIG. 4 is a schematic drawing showing a highly preferred embodiment of the invention having a vertical subterranean bed with multiple connecting portions.

FIG. 5 is a cross section of subterranean tunneling.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1-5 illustrate a preferred embodiment of an electrical-utility steam-turbine power-plant condensate cooling system (10) having subterranean horizontal tunneling having multiple connecting portions (24), an inlet portion (12), a discharge and cooling portion (14). Substantially all of the cooling portion (14) is a closed-loop tunneling system (16) beneath the surface (18) of the Earth as seen in FIGS. 1 and 3. Water (20) substantially fills the closed-loop system (16) and pump (22) facilitates flow through the closed-loop system (16) whereby water (20) flowing through the tunneling (16) is geothermally cooled.

As illustrated in FIGS. 1 and 3, a highly preferred embodiment has tunneling (16) configured in a generally horizontal direction. In an alternate embodiment, tunneling (16) is in a generally vertical configuration and is substantially located within the Earth as seen in FIGS. 2 and 4. The bed of tunnels (16) is ideally in a horizontal configuration but can be constructed in a vertical configuration if space is limited.

FIGS. 3 and 4 illustrate that tunneling (16) has multiple connecting portions (24) and water (20) flows between the tunneling (16) in substantially one direction. As illustrated in FIG. 5, tunneling (16) is comprised of piping (26) and includes a lining material (28). Lining material (28) is preferably materials such as concrete, metal and fiberglass. The cooling system (10) of this application is a replacement for an industrial cooling-tower cooling system.

Tunneling (16) is bored into a suitably impermeable Earth material such as obsidian, granite or other dense Earth materials, at a depth which provides a constant temperature adequate to cool the heated water (20) within the targeted parameter.

As seen in FIGS. 3 and 4, tunneling (16) would consist of at least two main tunnels (30), one tunnel serving as an inlet tunnel (32) the other as a discharge tunnel (34). Inlet and discharge tunnels (32, 34) are sized to accommodate the necessary volume of water (20) and may have check valves (48). Inlet and discharge tunnels (32, 34) would include a series of connecting tunnels (36) located along the length of the inlet and discharge tunnels (32, 34) as illustrated in FIGS. 3 and 4. It should be appreciated that the connecting tunnels (36) would be of somewhat different diameters to compensate for the distance traveled by the incoming water (20) such that the volume flow be as equal as possible in order to achieve the highest heat exchange rate available.

FIGS. 1 and 2 illustrate that cooling system (10) preferably includes more than one pump (22), the at least one pump (22) maintains adequate water (20) flow through closed-loop system (16). Pump (22) is preferably placed at the inlet end (38) of the inlet tunnel (12) to ensure appropriate water (20)flow. Alternatively, pump (22) may be located at the discharge portion (14), or ideally, pumps (22) can be located at both the inlet (38) and discharge ends (40). Pumps (22) on the inlet (38) and discharge ends (40) preferably have balance flows so as not to cause a buildup of pressure or vacuum in tunneling (16).

It should be appreciated that the ability to cool water (20) to the preferred range is dependant upon the volume of cooling fluid (42), the heat-exchange properties of the Earth material through which the water (20) travels and the distance of travel of the water (20) within the tunneling (16). It should also be appreciated that if water (20) is cooled to a lower temperature in the tunneling (16), than water (20) which is cooled using a traditional cooling tower, the efficiency of the condensate cooling system (10) is improved. Condensate cooling system (10) also does not release extra water vapor into the atmosphere. This is another improvement over systems utilizing traditional cooling towers.

The invention also includes an inventive method of cooling condensate water (20) in an electrical-utility steam-turbine power-plant cooling system (10). The following steps are highly preferred in the method. Water (20) is pumped through subterranean tunneling (16) having a connecting portion (36) at the distal ends (44) thereof; whereby water (20) flowing through tunneling (16) is geothermally cooled.

In operation, the condensate cooling water (20) is pumped through tunneling (16) and is cooled by the geothermal temperature differential. Cooled water (20) is then pumped through a heat exchanger (46) wherein condensate is cooled and the heated condensate cooling water (20) is recirculated through the cooling system (10).

A wide variety of materials are available for the various parts discussed and illustrated herein. While the principles of this invention have been described in connection with specific embodiments, it should be understood clearly that these descriptions are made only by way of example and are not intended to limit the scope of the invention. 

1. In an electrical-utility steam-turbine power-plant cooling system of the type having (a) a condenser with heat-exchange surfaces and (b) cooling means therefor, the improvement wherein the cooling means comprises: a closed-loop system having an intake, a discharge and a cooling portion, substantially all of the cooling portion being tunneling beneath the surface of the Earth: water substantially filling the closed-loop system; and a pump to facilitate flow through the closed-loop system; whereby the water flowing through the tunneling is geothermally cooled.
 2. The cooling system of claim 1 wherein the pump is more than one pump.
 3. The cooling system of claim 1 whereby the at least one pump maintains adequate water flow through the closed-loop system.
 4. The cooling system of claim 1 wherein the cooling system is a replacement for an industrial cooling-tower cooling system.
 5. The cooling system of claim 1 wherein the tunneling is in a generally horizontal configuration.
 6. The cooling system of claim 5 wherein the tunneling has multiple connecting portions therebetween whereby water flows between the tunneling in substantially one direction.
 7. The cooling system of claim 1 wherein the tunneling includes a connecting portion located within the Earth in a vertical configuration.
 8. The cooling system of claim 7 wherein the tunneling has multiple connecting portions therebetween whereby water flows between the tunneling in substantially one direction.
 9. The geothermal cooling system of claim 1 wherein the tunneling includes a lining material.
 10. The geothermal cooling system of claim 1 wherein the tunneling is comprised of piping.
 11. A method of cooling condensate water in an electrical-utility steam-turbine power-plant cooling system comprising the steps of: pumping water through subterranean tunneling having a connecting portion at the distal ends thereof; whereby causing the water flowing through the tunneling to be geothermally cooled. 